The invention relates generally to implementation of services in a telecommunications network, particularly an intelligent network. The service may be any service produced in the network for a network user or another object.
The rapid evolvement of the telecommunications field has afforded operators the capability of providing many different types of services to users. A network architecture that provides advanced services is called an intelligent network. The common abbreviation for intelligent network is IN.
The functional architecture of an intelligent network is shown in FIG. 1 where the functional entities of the network are shown as ovals. This architecture is described briefly below, because the invention will be described hereinafter with reference to the intelligent network environment.
The access of the end user (subscriber) to the network is handled by the CCAF (Call Control Agent Function). The access to the IN services is implemented by making additions to existing digital exchanges. This is done by using the basic call state model BCSM which describes the existing functionality used to process a call between two users. The BCSM is a high level state automaton description of the call control functions CCF required for establishing and maintaining a connection route between users. Functionality is added to this state model by using the service switching function SSF (cf. the partial overlap of the entities CCF and SSF is FIG. 1) so that it is possible to decide when it is necessary to call the services of the intelligent network (the IN services). After these IN services have been called, the service control function SCF that contains the service logic for the intelligent network handles the service-related processing (of the call attempt). The service switching function SSF thereby connects the call control function CCF to the service control function SCF and allows the service control function SCF to control the call control function CCF. For example, SCF can request that the SSF/CCF perform specific call or connection functions, for example charging or routing operations. The SCF can also send requests to the service data function SDF which handles the access to the service-related data and network data of the intelligent network. The SCF can thus for example request the SDF to retrieve specific service-related data or update this data.
The functions described above are further complemented by the specialized resources functions SRF which provides the special functions required for implementing some of the services provided by the intelligent network. Examples of these services are protocol conversions, speech recognition, voice mail, etc. The SCF can, for example, request the SSF/CCF functions to first establish a connection between the end users and SRF and then it can request the SRF to give voice announcements to the end users.
Other functional entities of the intelligent network are various functions that relate to control, such as the SCEF (Service Creation Environment Function), SMF (Service Management Function), and SMAF (Service Management Access Function). The SMF includes, among other things, service control, the SMAF provides the connection to the SMF, and the SCEF makes it possible to specify, develop, test and feed IN services via the SMF to the SCF. Because these functions only relate to the operation of the network operator, they are not shown in FIG. 1.
The role of the functional entities described in FIG. 1 as relating to the IN services will be briefly described below. The CCAF receives the service request given by the calling party. The service request usually consists of lifting the receiver and/or a series of digit dialed by the calling party. The CCAF further transmits the service request to the CCF/SSF for processing. The call control function CCF does not have the service data but it has been programmed to recognize the need of a service request. The CCF interrupts the call setup for a movement and notifies the service switching function SSF about the state of the call. The task of the SSF is, using predefined criteria, to interpret the service request and thus determine whether the request is a service request related to the IN services. If this is the case, the SSF composes a standardized IN service request and sends the request to the SCF along with information about the state of the service request. The SCF receives the request and decodes it. After that it cooperates with the SSF/CCF, SRF, and SDF to provide the requested service to the end user.
The physical level architecture of the intelligent network describes how the functional entities described above are located in the physical entities of the network. The physical architecture of the intelligent network is illustrated in FIG. 2, where the physical entities are described as rectangles or circles and functional entities as ovals. The signaling connections are described by dashed lines and the actual transport which is for example speech, by continuous lines. The optional functional entities are denoted with dashed line. The signaling network shown in the Figure is a network according to SS7 (Signaling System Number 7 is a well-known signaling system described in the CCITT (nowadays ITU-T) blue book Specifications of Signaling System No. 7, Melbourne 1988).
The subscriber equipment SE which can include, for example, a telephone, computer, or telefax, are connected either directly to a service switching point SSP or to a network access point NAP.
The service switching point SSP provides the user with access to the network and handles all necessary selection functions. The SSP can also detect any IN service request. Functionally, the SSP includes the call control and service selection functions.
The network access point NAP is a traditional telephone exchange that includes the call control function CCF, for example, the Applicants"" DX 220 exchange which can differentiate calls that require IN services from traditional calls and route the calls that require IN services to the appropriate SSP.
The service control point SCP includes the service logic programs SLP that are used to produce the IN services. The shorter term service program will also be used for service logic programs in the following.
The service data point SDP is a database containing customer and network data which is used by the service programs of the SCP to produce tailored services. The SCP can use SDP services directly via the signalling or data network.
The intelligent peripheral IP provides special service, such as announcements and voice and multiple choice recognition.
The service switching and control point SSCP consists of the an SCP and SSP located in the same network element (in other words, if the SSP network element shown in the drawing contains both an SCF and an SSF entity, the network element in question is an SSCP).
The tasks of a service management system SMP include the management of the database(SDP), network monitoring and testing, and collecting network data. It can connect to all other physical entities.
The service creation environment point SCEP is used for specifying, developing and testing the IN services, and for entering the services in SMP.
The service adjunct AD is functionally equivalent to the service control point SCP, but it is directly connected to SSP with a fast data connection (for example, with an ISDN 30B+D connection) instead of via the common channel signalling network SS7.
The service nodes SN can control the IN services and perform data transfers with users. It communicates directly with one or more SSPs.
The service management access point SMAP is a physical entity which provides certain users with a connection to SMP.
The above is a brief description of the intelligent network as a background to the description of the method according to the invention. The interested reader can get a more detailed description of the intelligent network in, for example, ITU-T specifications Q.121X or in the AIN specifications of Bellcore.
It should be possible to provide IN-based services to subscribers in fixed or mobile networks in a way enabling provision of tailored service in such a way that a specific subscriber-associated combination of service features can be offered to each individual subscriber as easily as possible. All services provided to customers or subscribers consist of one or more service features SF. A service features is the (smallest) component, visible to the customer or subscriber, that the service obtained by him/her comprises. The subservice, for which the above term xe2x80x9cservice featurexe2x80x9d is employed in the international standards, is termed a feature in the present context.
From the point of view of service designers, an intelligent network is divided into service independent building blocks for which the abbreviation SIB is used. The SIBs are blocks from which service designers assemble service features and services. In other words, SIBs are the smallest blocks from which services and service features are assembled. A service consists of several service features and a service feature again consists of several SIBs, even though in some cases a service feature may consist of only one SIB.
The international standards define the service independent building blocks of which services shall be composed. When, moreover, the situation has been such that network operators have wanted new services in their networks as fast as possible, it has been thought that this task can best be fulfilled when the actual service logic programs are implemented as modules complying with the block division specified in the standards. Thus, one has started to implement service programs as functional blocks (modules) that correspond to the SIBs specified in the standards as closely as possible.
However, such a solution has proved difficult, since it is necessary to implement within the blocks also a lot of functionality that is not directly related to the service logic needed by the subscriber but serves the internal function of the network element. In addition to INAP messages arriving from the network, other messages internal to the network element must be used, wherewith information not included in the INAP messagesxe2x80x94e.g. parameters of the data tables of the network elementxe2x80x94is transmitted. Furthermore, it must be possible to exchange e.g. error and acknowledgement messages between the service logic programs and the network element platform.
Therefore, in the present situation it is difficult to create new tailored services. The difficulty will be enhanced even more if services are needed rapidly for example for temporary use.
It is an object of the invention to eliminate the above-described drawback and to provide a solution wherewith the implementation of services can be made simpler and faster than heretofore.
This object is achieved with the method in accordance with the invention, which is defined in the independent claim.
The idea of the invention is to use a dedicated messaging SIB for each different type of message to be sent to the network, and each time the message to be sent is such that a related response must be awaited before the service logic is continued, a generic halt state SIB is used that receives said response. The idea is thus to divide network functions in a novel way into building blocks (SIBs) and additionally to use these building blocks in such a way that a block sending a message of a given type is always succeeded by a block of a given type (generic halt state block) in which a message of said type is awaited from the network.
On account of the solution in accordance with the invention, a very significant relief is achieved in the implementation of services, since the service logic needed by the subscriber or customer can be clearly distinguished from the internal logic of the network element, and the internal logic of the network element can be made transparent to the producer of the service. This is due to the fact that the reception logic required by all possible responses need no longer be placed within the building blocks of different types when one is awaiting a specific message from the network within the block.
A further advantage of the solution of the invention is that operators can easily create different services for examples for temporary test use in order to test the services for example before one starts creating a management system for them.